Aerially launched marine mine



Jan. 23, 1962 A. BARRY 3,

AERIALLY LAUNCHED MARINE MINE Filed Aug. 24, 1948 3 Sheets-Sheet 1 fHwv/WV'W Adelbert Barry Jan. 23, 1962 A. BARRY AERIALLY LAUNCHED MARINE MINE 5 Sheets-Sheet 2 Filed Aug. 24, 1948 Adelbert Barry Jan. 23, 1962 A. BARRY AERIALLY LAUNCHED MARINE MI 5 Sheets-Sheet 3 Filed Aug. 24, 1948 gnaw/W Adelbert Barry 3 ,0 l @331 Patented Jan. 23, 1962 s,017,ss1 AERIALLY LAUNCHED MARlNE MHJE Adelhert Barry, 2123 Kingston Drive, Heuston 6, Tex. Filed Aug. 24, 1 .948, Ser. No. 45,961 5 Claims. (Cl. 102-10) (Granted under Title 35, US. (lode (1952), sec. 266) This invention relates to marine ground mines and more particularly to a mine of this character which is adapted to be launched from an aircraft in flight without auxiliary means for retarding the free flight of the mine through the air and without causing damage to the mine casing or to the firing mechanism contained therewithin as the mine strikes the surface of the water or comes to rest on the bed thereof.

The present invention further contemplates a new and improved mine casing having an off-center ogival nose construction which reduces the shock of impact of the casing with the surface of the water and becomes effective as the mine enters the water to reduce the rate of descent of the mine therein whereby the mine may be planted in a shallow body of water Without becoming embedded in mud on the bed thereof or damaged upon impact when the surface of the bed is hard.

In mines heretofore devised of the type adapted to be planted on the bed of the body of water from an aircraft in flight, it has been the usual practice to employ a retarding means such, for example, as a parachute for reducing the rate of descent of the mine through the air. in certain prior art cases in which no flight retarding means is employed, the mine casing is provided with a nose of unsymmetrical shape to cause the mine to veer from its normal path of descent within the Water sufficiently to reduce the downward velocity of the mine. The flight of the mine through the air, however, is maintained along a predetermined line of travel notwithstanding the unsymmetrical nose of the casing by the provision of a fairing which becomes detached from the casing upon impact of the mine with the surface of the water and, prior to removal, provides the mine with a symmetrical cylindrical casing having a flat or rounded nose portion. Such a mine, for example, is disclosed and claimed in the copending application of John I. Thompson et al., Serial No. 523,088, filed February 19, 1944, now Patent 2,472,866, dated June 14, 1949.

The path of travel of the mine through the air along the predetermined line of flight is usually further controlled by a plurality of fins formed integrally with or secured to the mine casing, as the case may be.

In certain of the prior art mines, the parachute also acts as a drogue to limit the downward velocity as the mine descends through the water. Mines having releas able parachutes, however, have not been found to be entirely satisfactory in service for the reason that the mine may be free to accelerate when the parachute is released and the mine may reach a relatively high velocity as it strikes the bottom. In such case, the shock of impact might be suflicient to damage or prematurely actuate the firing mechanism of the mine.

Hydrostatic control means adapted to be actuated to release the parachute at the termination of an appreciable interval of time have not been found to be entirely satisfactory in service for the reason that a mine employing such control means may be dragged away from the target area of the mine by channel or tidal currents acting on the parachute before the mine is released from the parachute. Mines employing this release means have the additional disadvantage in that a demolition crew, acting quickly, may recover the mines by fouling the parachute with a sweep wire before the mines are released therefrom.

A mine constructed in accordance with the present invention, retains all of the advantages of the prior mines of this general type and possess none of the foregoing disadvantages. More specifically, an arrangement is provided in which the mine is adapted to be launched at high altitudes and guided through the air along a predetermined line of flight without the need for a parachute or other retarding device. The course of the mine within the water is abruptly changed by reason of the provision of a member which is forcibly detached from the casing of the mine as the mine strikes the surface of the water to expose a control surface to the water which reduces the shock of impact of the mine with the surface of the water and causes the mine to be deflected from its initial downward course and to engage the bed of the body of water at a greatly reduced rate of travel, whereby the mine comes to rest on the bed without damage to the casing or to the sensitive firing control mechanism arranged therein arid further protected from shock by the provision of a resilient mounting for the mechanism within the casing.

According to the arrangement of the present invention, the mine casing is formed of symmetrical cylindrical configuration and is constructed of several body portions including a heavy cast steel ogival nose, a relatively heavy main body portion for housing the explosive charge and the arming and firing mechanism of the mine, and light weight body portions which form the tail structure for guiding the free flight of the mine through the air and a fairing for housing the ogival nose which is formed on the forward portion of the main body portion with the apex thereof off-center and is effective to reduce the impact forces on the mine casing by reason of the arched surfaces thereof and to cause the aforementioned deflection of the mine Within the water by reason of the olfcenter apex of the ogival nose as the faired portion is detached therefrom upon impact with the surface of the water.

It has been found as a result of extensive experimentation conducted by the United States Government that when the nose and main body portions of the casing are constructed, as in the manner hereinafter more fully to be set forth, the mine may be dropped from altitudes upwards of 20,000 feet without causing damage to the casing upon impact with the surface of the water or with the bed thereof sufficient to damage or otherwise impair the effectiveness of the casing or of the arming and firing mechanism for the purpose intended.

It has been found as a result of governmental experimentation that an off-center nose surface constructed according to a predetermined pattern of a specific form more fully to appear as the description proceeds, causes the mine to veer from its initial trajectory path within the water when the fairing has been forcibly removed from the nose as the mine strikes the water. nose surface causes the mine to veer from the initial trajectory, the water velocity past the tail of the mine removes the tail fin structure. This occurs when the mine has descended within the water to a depth of approximately ten feet. The fairing and tail structure preferably have negative buoyancy whereby these parts sink to the bed of the body of water and thus avoid detection of the mine by the presence of such parts on the surface of the Water.

When the mine has reached a depth of approximately 20 feet in the water, the off-center nose has caused the mine to present itself broadside or with the longitudinal axis thereof at right angles to the path of travel of the mine within the water, and the mine retains this broadside position until it reaches a depth of approximately 60 feet at which time it has lost the greater part of its entry velocity and thereafter noses down slightly and picks up in velocity until the velocity becomes sufficientr As the ogival to cause the nose to again broadside the mine. When the water depth is in the order of 100 feet, the mine may broadside twice before reaching the bed of the water. In cases of more shallow depths, however, the initial broadsiding slows the mine down sufliciently to prevent any damage to mine or components in water as shallow as forty feet.

An object of the present invention is to provide a new and improved marine ground mine adapted to be launched at a high altitude from an aircraft in flight without the need for auxiliary means for retarding the downward descent of the mine through the air and/or water.

Another object is to provide an aen'ally launched marine mine having provision for launching the mine from a high altitude without auxiliary means for retarding the free flight of the mine through the air and without causing damage thereto upon impact with the surface of the body of water or with the bed thereof.

Another object is to provide a casing construction for an aerial marine mine having provision for guiding the mine along predetermined paths of travel within the air and water and for preventing damage to the casing or the arming and firing mechanisms contained therein upon impact of the mine with the surface of the water and with the bed thereof.

Another object is to provide a mine casing having a specific construction effective to withstand the shock of impact of the mine during the launching operation and having provision for resiliently mounting a delicate firing mechanism therewithin to lessen the shock received by the mechanism during the launching operations.

Another object of the present invention resides in the provision of a new and improved ogival nose construction for reducing the velocity of an aircraft planted mine during the travel of the mine through the water.

Another object is to provide a new and improved mine casing construction having provision for causing the mine to follow a predetermined course of travel during the free flight thereof through the air and during its movement through the water.

A still further object is to provide a new and improved nose structure for an aerial launched marine mine having no provision for auxiliary flight retardation in which the nose is adapted to withstand without damage thereto the shock of the impact of the mine with the surface of the body of water.

An additional object resides in the provision of an offcenter ogival nose for a mine casing in which the surface of the nose conforms to a predetermined pattern effective to lessen the shock of impact of the mine casing with the surface of the water and to guide the mine along a predetermined path within the water.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a view of a mine in accordance with the preferred embodiment thereof, the casing being shown in section;

FIG. 2 is a view taken along line 2-2 of FIG. 1;

FIG. 3 is a View taken along line 33 of FIG. 1;

FIG. 4 is a view taken along line 44 of FIG. 2;

FIG. 5 is a view taken along line 5--5 of FIG. 1; and

FIG. 6 is a diagrammatic view illustrating the path of travel of the mine as the mine is launched from an aircraft in flight to come to rest on the bed of a body of water within the target area.

Referring now to the drawings for a more complete understanding of the invention and more particularly to FIG. 1, there is shown thereon a mine indicated generally by the numeral 10 and comprising a generally cylindrical casing 11, of substantial thickness such, for example, one quarter to three eighths of an inch and having the rear? ward end thereof sealed by a cover 12 secured thereto as by bolts 13- with a suitable gasket, not shown, interposed between the cover and the casing to insure a watertight joint therebetween as the bolts are tightened. The forward end of the casing 11 is enclosed by a heavy cast steel ogival nose portion 24 which is constructed from a special type steel such, for example, as that known in the trade as A-1330 steel which has the desired strength and magnetic properties suitable for use in a magnetic influence type mine of the character disclosed herein. It will be understood that the casing must not be effective to diminish the flux pick up power of the search coil and thus render the firing control system insensitive to changes in the ambient magnetic field caused by vessels moving in the vicinity of the mine and thereby defeat the very purpose for which the mine is intended, namely to detect and effectively damage or destroy the passing vessel.

The apex 14 of thenose is formed off-center with relation to the longitudinal axis of the casing approximately 28% of the diameter thereof, and the surface of the nose portion is curved from the apex of the nose rearwardly along a pair of arcs 19 and 20 of predetermined radii whereby the rear surface of the nose portion merges into the cylindrical side wall of the casing. The surface of the nose is developed from these arcs such that transverse cross sections through the nose normal to the longitudinal axis of the casing define progressively increasing circles on the nose surface as the sections are taken progressively rearwardly of the nose apex. The nose portion 24 is secured to the casing 11 in any suitable manner effective to provide a shock proof joint therebetween, preferably as by welding as at 40.

The ogival nose portion 24 presents an angular forward surface which cleaves the Water as the casing enters thereinto whereby the force of impact of the mine with the surface of the water is substantially lessened. Moreover, only a component of the impact force is applied to the nose surface in a direction opposing the movement of the mine into the water for the reason that pressure is always applied normal to the pressure receiving surface which, in this case, is not normal to the axis of the casing and therefore is not parallel to the surface of the water. Thus, the impact force is received by the casing at an angle to the longitudinal axis thereof with a resultant component force of lesser value applied in a direction opposing the movement of the mine into the water whereby the shock resulting from the water entry is greatly reduced.

The off-center ogival nose portion 24 presents an unsymmetrical front or forward end of the mine casing disposed at an angle with respect to the direction of movement of the mine through the water whereby the pressure of the water against this control surface causes the mine to veer from its initial trajectory path within the water, as illustrated in FIG. 6, thereby to cause the tail structure to be forcibly removed from the mine by the force of the water moving at high velocity past the tail of the mine and to cause the mine to decelerate during further descent thereof sufficiently to bring the mine to rest on the bed of the water without damage to the mine casing or the mine firing and arming mechanism contained therein. The nose portion 24 is provided with a thick wall portion 25 which is further strengthened with reinforcing rib 26 formed therein.

The aforedescribed mine casing is particularly well suited for use with a magnetic induction type mine firing control system which may be similar to that disclosed and claimed in the copending application of W. D. Mounce et al., for Mine Firing Control System, Serial No. 500,399, filed August 28, 1943, in which the elements comprising the sensitive firing mechanism of the system are formed of non-moving parts which are enclosed within the mine casing in such a manner as to prevent damage to the elements in response to the shock of impact as the mine strikes the water.

When used with the instant mine casing, the search coil 33 of the firing system is housed in a protective sheath 32 which is supported on one end thereof within a well 31 formed on the wall 29 of casing 11 and on the other end thereof within a recess 34 formed in the projection extending inwardly within the nose 24 from the apex thereof.

There is also arranged within the casing 11 a well 38 within which is arranged the usual extender mechanism 35 which is adapted to move an electroresponsive detonator 47 into proper firing relation with respect to a booster charge 48 contained within a housing 49 when the mine has been submerged within the water for a predetermined interval controlled by a soluble washer, not shown.

There is also arranged within well 38 a hydrostatic device 46 adapted to set an arming clock 37 contained in housing 36 into operation when the pressure of the water surrounding the mine has reached a predetermined value.

A battery 39 and a mine firing mechanism 41 are disposed within a housing 42 extending transversely of the end wall 29 with a fairly hard rubber cushion 45 completely surrounding the battery 39 and firing mechanism 41, a suitable rubber or substitute resilient material therefore having a hardness of about durometer. The cushions are forced between the cylindrical surface of the battery, mechanism, and housing 4-2 by longitudinally arranged bolts 51 which upon tightening compress the cushions between end plates 52 and thus force the cushions inwardly into effective frictional locking engagement with the battery and mechanism and outwardly into effective locking engagement with the inner wall of housing 42 whereby axial movement of the battery and mechanism in response to the shock of impact is resiliently opposed and the shock to the mechanism as a result of such movement in substantially lessened.

A suitable water tight filler opening 43 is provided in casing 11 by means of which an explosive charge 44 of TNT or the like is inserted to entirely fill the casing 11 and the chamber formed within the nose 24 to further reinforce the walls thereof.

The casing 11 is preferably provided with brackets 17 and 18 thereby to facilitate the loading of the mine into the aircraft and, if desired, to secure the mine to the aircraft prior to the launching of the mine therefrom. A plurality of fin members 16 formed of frangible material and possessing negative buoyancy are provided with brace members 15 connected therewith which are secured to the casing 11 as by clamps 27 and bolts 28, the fin members being employed to steer the mine along a predetermined path through the air during the launching thereof and are adapted to be forcibly removed from the mine and sink to the bottom as the mine veers from its initial path of travel. It is animportant feature of the mine of the present invention that both the nose fairing and tail structure are removed upon water entry whereby the specific characteristic travel and performance of the mine within the water, as presently to be described in detail with reference to FIG. 6, is obtained in a manner effectively to reduce the rate of descent of the mine within the water.

The leading or forward end of nose portion of the mine is preferably enclosed by a cylindrical cup-shaped fairing 21, formed of frangible material having negative buoyancy such, for example, as a low pressure molded fabric base plastic which is secured to the casing 11 by a plurality of bolts 22 as shown. The fairing is adapted to provide the forward end of the casing with a symmetrical fiat surface and present a uniform wind resisting front to the air when the mine is released from the aircraft in flight thereby to maintain the flight of the mine along a predetermined path of travel through the air, the fiat surface of the fairing serving to reduce the velocity of descent of the mine through the air without causing the mine to deviate from its desired trajectory. The fairing is provided with a circular opening 23 therethrough in registry with the apex 14 of the nose 24. The opening 23 is adapted to admit water to the interior of the fairing to cause the fairing to be ripped clear of the casing as the mine strikes the surface of the water.

The launching operation of the mine will best be understood by reference to FIG. 6 wherein it will be seen that the mine upon falling away from the aircraft follows a substantially straight trajectory 53 through the air without deviation therefrom whereby the mine enters the Water substantially at right angles to the surface thereof and within a desired target area, the flat nose surface of the fairing 21, as stated hereinbefore, arresting the downward movement of the mine through the air. As the mine enters the water, the shock of impact of the nose of the mine with the surface thereof causes the fairing 21 to be ripped clear of the main body portion 11 of the mine thereby to expose the off-center ogival nose surface whereupon the mine is caused to veer from trajectory 53. This change in the trajectory path caused the tail structure 16 to be ripped clear of the main body portion 11 by the force of the water moving past the tail structure at high velocity, this being effected when the mine reaches the position indicated at 54 at which time the depth of the water may be in the order of ten feet.

With the movement of the mine now entirely under control of the off-center ogival surface, the mine moves to a position broadside of the trajectory path as indicated at 55 at which time the depth of water may be in the order of twenty feet. The water presents an effective opposition to the mine in the broadside position thereof whereby the mine has lost the greater portion of its entry velocity when the mine has continued broadside to a depth of approximately 60 feet as indicated at 56. Thereafter the mine begins to nose downwardly as at 57 and the downward velocity increases slightly as the mine moves successively to positions such as indicated at 58 and 59 whereby the mine gently comes to rest on the bed of the body of water as at 60.

In the event that the water is of greater depth, the downward velocity of the mine may increase to a value such that the ogival nose surface may again cause the mine to broadside, this occuring two or more times depending on the depth of the water. The broadside motion of the mine thus effectively arrests the rate of downward descent thereof within the water whereby the mine in any case is brought to rest on the bed of the water at a greatly reduced velocity of sufiiciently low value to prevent damage to the mine casing and delicate arming and firing mechanisms contained therein when the bottom is hard and to avoid submerging the mine beneath the surface of the bed when the bottom is soft.

It will be noted that the walls of the nose of the mine are of a substantial thickness and further strengthened by a reinforcing rib, and that the chamber formed within the nose and the casing is entirely filled with an explosive materal to further strengthen the mine structure sufficiently to withstand the shock as the mine strikes the surface of the water. Moreover, as set forth hereinbefore, the angular configuration of the off-center ogival nose lessens the shock of impact, thus making possible a mine structure which may be launched into the water from an aircraft in flight without the need for auxiliary motion retarding means.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In an aerially launched marine mine, a cylindrical casing, cylindrical frangible means immovably secured to the forward end of said casing and having a cross sectional portion circular in configuration and of the same diameter as the diameter of the casing to which it is secured for guiding the mine in a predetermined path of flight through the air and detachable therefrom in response to the impact of the mine with the water, and means on said casing for sharply changing the direction of the travel of the mine upon entry into the water and comprising a shell having an ogival end the apex thereof off-center with respect to said casing, the surfaces of the ogival end being curved rearwardly from said apex along predetermined different arcs of curvature, said curved surfaces merging into and forming a cylindrical portion secured to said cylindrical casing, said ogival end of the shell being disposed within said frangible means until the frangible means is detached from said casing.

2. In an aerially launched marine mine, a cylindrical casing, an unsymmetrical nose on one end of said casing,

frangible means symmetrical with said casing surrounding and enclosing said nose, said frangible means being adapted to be detached from said mine upon entry into the water, means on said casing for sharply changing the direction of travel of the mine upon entry of the mine into the Water and comprising a shell having an ogival end the apex thereof ofi-center with respect to the axis of said casing, the surfaces of the ogival end being curved rearwardly from said apex along predetermined different arcs of curvature, said curved surfaces merging into and forming a cylindrical portion having the terminal end thereof disposed within said cylindrical casing and secured thereto, and rib means disposed within and integrally formed with said shell for reinforcing the shell and having a recessed supporting element integrally formed therewith, said cylindrical portion forming a cylinder of substantially the same diameter as the diameter of the casing.

3. In a marine ground mine adapted to be planted in a body of water from an aircraft in flight, the combination with a cylindrical mine casing, a shell forming an impact nose for said casing, an ogival end formed on said shell with the apex thereof off-center with respect to the axis of the casing by an amount approximately equal to 28% of the diameter of the casing and having the surfaces thereof curved rearwardly from said apex along predetermined diiferent arcs of curvature, said curved surfaces merging into and forming a cylindrical portion secured to the cylindrical wall forming said mine casing, said curved surfaces being adapted to cause the mine to move broadside within the water thereby to suddenly reduce the rate of downward movement of the mine within the water, a symmetrical cylindrical fairing detachably secured to the shell at said cylindrical portion, said fairing encircling the shell and enclosing the ogival end thereof, for detachment from the shell as the mine strikes the water.

4. In a marine ground mine adapted to be planted in a body of water from an aircraft in flight, the combination with a cylindrical mine casing, a shell forming an impact nose for said casing, an ogival end formed on said shell with the apex thereof off-center with respect to'the axis of the casing and having the surfaces thereof curved rearwardly from said apex along predetermined different arcs of curvature, said curved surfaces merging into and forming a cylindrical portion secured to the cylindrical wall forming said mine casing, said curved surfaces being adapted to cause the mine to follow an erratic path of travel Within the water thereby to reduce the rate of downward movement of the mine within the water, an explosive charge disposed within and filling said shell for reinforcing the curved surfaces of the shell, a centrally disposed rib integrally formed within the shell and encompassed by said charge for additionally reinforcing the curved surfaces of the shell, and a cylindrical cup-shaped symmetrical fairing of substantially the same diameter as the casing detachably secured to the shell in alignment therewith and encircling said impact nose for presenting a uniform wind resisting front to the air during descent therethrough, said fairing having an aperture opposite the apex of said nose whereby water entering the aperture causes the fairing to be forcibly detached from the shell as the mine strikes the water.

5. In a mine of the character disclosed adapted to be planted in a body of water from an aircraft in flight, the combination with a cylindrical casing for said mine, and having a mine firing search coil arranged therein, a shell forming an impact nose for said casing, an ogival end formed on said shell with the apex thereof off-center with respect to the axis of the casing and having the surfaces thereof curved rearwardly from said apex along predetermined different arcs of curvature, said curved surfaces being adapted to cause the mine to follow an erratic path of travel within the water thereby to reduce the rate of downward movement of the mine within the water, said curved surfaces merging into and forming a cylindrical portion of substantially the same diameter as said casing and secured thereto, a centrally disposed inwardly extending rib integrally formed with the shell and bordering on said curved surfaces for reinforcing said shell, and a circular support integrally formed with said rib and having a recess formed therein for receiving and supporting said search coil.

References Cited in the file of this patent UNITED STATES PATENTS 41,112 Willoughby Ian. 5, 1864 1,161,461 Dodgson Nov. 23, 1915 1,290,829 Carpentier Jan. 7, 1919 1,382,166 Blum June 21, 1921 1,442,345 Kee Jan. 16, 1923 1,923,612 Bull Aug. 22, 1933 2,472,866 Thompson et al June 14, 1949 FOREIGN PATENTS 338,064 Great Britain Nov. 13, 1930 346,266 Italy Feb. 5, 1937 539,699 Great Britain Sept. 22, 1941 

